Method of obtaining strontium from mixed solutions



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Patented Nov. 10, 1931 COULTER w. JONES, 0F mnnannnronr COMPANY, MIDLAND,-MICHIGAN, A CORPORATION OF MICHIGAN METHOD or OBTAINING smomwn'mm MIXED] sonurrons Io Drawing.

. This. inventionrelates to the obtaining of strontium 'compounds'from mixed solutions, and particularly from brines including calcium chloride, and it is among the objects of the invention to provide a method making possible such separation in a'ma-nnernot requiring elaborate precipitations with added agents, etc. Other objects and advantages will appear as the description proceeds.

To the accomplishment of the foregoing and related ends. the invention, thenconsists I V for to stop the cooling short of a temperature.

of the features hereinafter fully described, and particularly pointed out in the clalms, the following description setting forth in detail but one of the various ways in which the principle of the invention may be employed.

Strontium present amounts in brines containing calcium chloride and other chlorides may be largely separated therefrom by selective crystallization and temperature. The method is applicable in general to mixed brines containing cal-- and strontium chlorides applicable to separation cium. magnesium, and is particularly of strontium from mother liquors obtained from natural cium chloride from which sodium chloride has been removed by concentration and salting out'and which may or may not have also been worked for magnesium chloride'or other salts present.

In general I concentrate the brine to remove the sodium chloride. if present, by salthloi119, out and filtration. It magnesium c ride be present in considerable amounts it may be removed largely as tachydrite by con- C. The

. centration and cooling to about 60 mother liquor contains principally calcium of the strontium originally present. If this liquor or mixed chloride liq-.

chloride and most uors containing strontium have a strength such that when cooled. they will become saturated as to hydrated chlorides of calcium and strontium, a crop of crystals will separatev out contaming the strontium in higher proportion than in the original liquor. For example. a brine containing approximately parts of calcium chloride to 1 part M Cl and 1% strontium chloride or less, from even in relatively small:

or mixed brines containing; calcooling range is by choosing solutions crystallizations of. the crop. contain ng the Application -fi1ed Aug'ust 29, 1927. Serial no. 216,333.

which brine salt has been previously removed Wlll, 1f brought to a gravity of approximately 49B. at 46 (3., and then cooled to about31 (1, separate out a crop of hydrated crystals, containing chiefly were present, this excess would also separate out with the hydrated chlorides.

With a solution of that concentration I presaturated pure water solution, but for a solu eAN,..AssIeNon To. run now cnnmrcania tion of mixed chlorides the transition tem- 'pe'rature may be'slightly difierent.

= {Slow cooling near the saturation point is advisable and it is desirable also to agitate.

the solution; Depending upon the 'particu lar relative concentrations, the crystalsmay run veryrlow" in strontium chloride andin such event they may be recrystallized, to concentrate the strontiumsalt or they may be,

'further'concentrated by selective melting and draining Preferably -jcrop of crystals from the mother liquonand I separate the heat tomelt a portion which runs away as a strong calcium chloride solution, leaving the... strontnun 1n hlgher concentration;

. The cooling to produce the crystalscon- "taining strontium may indeed be carried to a point below CaClQtSI-LO will separate. This procedure the. temperature at which produces a larger crop relativeto the actual strontium-removed. although with afsuflicient total a larger extraction of strontium may thereby be had. Selective melting may then be practiced to concentrate the strontium: content in the remaining, crystals, the leachings beinq returned to the cooling step for recrystalllzation. To obtain the strontium in higher concentrations recrystalliz'ations of the residue may be resorted to. I i

The above example illustrates procedure applied to concentrated solutions where'the limited to around 31 0., but of lessconcentration left from the separation of magnesium chloride in the form of tachydrite, but its advantages may also be realized with other solutions such as mixed or natural brines containing calcium chloride, magnesium chloride, strontium chloride, and other salts, and in instances of salts other than chlorides it may be applied also by firstconverting the contained salts to chlorides.

Other modes of applying the principle of the invention may be employed, change being madeas regards the details disclosed, provided the steps stated bv any of the following claims or the equivalent of such be employed.

I therefore particularly point out and dis- 1 tinctly claim as my invention 1. A method of removing'strontium' salts from mixedso utions containing calcium and magnesium chlorides in the approximate ratio of 10 to 1 and having a ravity of 48 B. to 49 B. at 46 C. which comprises coolinq such solution to about3l C. wh le agitating, separating :the crvstals formed, and further purifying the strontium chloride so crystallized.

2. A method of removing strontium chloride from a solution containing calcium ch oride wherein the former is present in relatively small proportion to the atter which comnrisesconcentratino' such solution to saturation with respect to ca at a temperature of about 31 and coolino temp ra ure C..or lower. such concentrated so ution to a not materially lower-than the aforesaid point of saturation whe ehv crysa temperature of about 31 0., or lower, cooling such concentrated solution to a temperature not materially lower than the aforesaid point of saturation whereby crystals of the hydrated mixed chloridesof calcium and strontium are precipitated containing the strontium in greater proportion than in the original solution, separating the crystals, partially melting the same and separating the liquid from the residual crystals containing a further increased chloride.

'5. In amethod of separating strontium chloride from a mixture of same with crystals of calcium chloride hexahydrate, the steps which consist in partially melting such crystals and separating the liquid from the residual crystals containing a higher percentage of strontium chloride than the original crystals.

Signed by me this 19th day of August, 1927.

I COU'LTER W. JONES.

lcium ch oride tals of the hvdr ted mixed chlori es of calcium and strontium are precipita ed containing the strontium in greater proportion than in the orig na solution. 3. A method of removing strontium chloride from a solution containing calcium chloride wherein the I tivelv small proportion to the latter which comprises concentrating such solution to saturation with respect to calcium chloride at a temperature of about 31 ture not materially lower point of saturation whereby crystals of the hvdrated mixed chlorides of calcium and strontium are precipitated containing the strontium in greater proportion than in the original solution, separating the crystals and further purifying the same to increase the strontium chloride content thereof.

4. A method of removing strontium chloride from a solution containing calcium chloride wherein the former is present in relatively small proportion to the atter which comprises concentrating such solution to saturation with respect to calcium chloride at (lyor lower. coolf mg such concentrated solution to a temperathan the aforesaid V proportion of strontium former is present in relaw 

